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THOMSON TECHNICAL COMMUNICATION
Television
Troubleshooting Flow Chart
TFC-04061
The information contained herein is provided solely to assist qualified Technician in the diagnosis of the problem described. It is not intended as a modification or alteration of the product.
REVISION DATE: Chassis: CTC211 9/23/2004
TOPIC: YPrPb Signal Troubleshooting SYMPTOM: No YPrPb Video
1
1A
Is the 1H/2H YPrPb signals present at U22402, pins 2, 5, and 12?
No
Check the input jack J22401 for connection problems and zener diodes CR22401, CR22402, and CR22403 for shorted state. Also check coupling capacitors C22402, C22403, and C22404.
Yes
2
2A Check the VCC at pin 16 (9vdc) and check the logic switching at pins 9, 10, and 11 of U22402 (should be low in 1H YPrPb mode) . If the voltage is high, reinitialize the eeprom with Chipper Check. If all voltages check ok, suspect U22402.
Is the 1H/2H YPrPb signals present at pins 4, 14, and 15 of U22402?
No
Yes
Go to Page 2
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 1 of 4
THOMSON INC.
3
3a
Are the 1H/2H YPrPb signals present at pins 1, 2, and 3 of U22401?
No
Check transistors Q22402, Q22410, Q22403, Q22409, Q22405, and Q22411.
Yes 4 4A
2H YPrPb
1H YPrPb
Go to Page 3 5 5A
Are the YUV signals present at pins 14 (Y), 12 (U), and 10 (V) on J22403?
No
Check cabling and connectors J22403 and J32201. If these test ok, the Scan Rate Converter may be pulling the signal low.
Yes 6 6A
Are the 2H YPrPb signals present at pins 12 (Y), 10 (Pr), and pin 8 (Pb) on J22402?
No
Suspect a problem with the Scan Rate Converter board.
Yes
Go to Page 3
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 2 of 4
THOMSON INC.
7
Converted 2H YUV
8B
8 Are the Converted 2H YPrPb (YUV) signals present at pins 14 (Y), 15 (U), and 13 (V) on U38200 (i-o board)?
8A
2H YPrPb
No
Check U22404, U22405, and U22406. Check for correct switching at pin 9 on U38200 (high for internal signal). If these test ok, suspect U38200.
Yes
9 Are the YUV signals present at pins 14 (Y), 15 (U), and 13 (V) on U22401
9A Check for correct switching at pins 10 on U22401 (low for internal signal). I f the switching is correct, suspect U22401.
No
Yes
Go to Page 4
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 3 of 4
THOMSON INC.
11
11A Check the Luma-Chroma output signals at pins 13, 14, and 15 of U22401. If these are missing, check the switching (low) at pins 9, 10, and 11 of U22401. If this voltage is correct , suspect U22401.
Are the Luma and Chroma signals present at pins 51 (sel 2H-v), 52 (sel 2H-u), and 53 (sel 2H-y) of U22300?
No
Yes 12 12A
Are the Drive signal outputs present at pins 41, 42, and 43 of U22300?
No
Check the FSW at pin 36 of U22300, the "sense in" at pin 56 (should be 2.6vdc), and the "ABL" circuit at pin 45 (4.5-6.0vdc). If all these test ok, reinitialize U13102 or suspect a defective U22300.
Yes
13 Check for output drive signals at pin 12 of U25101 (red), U25301 (green), and U25501 (blue). If these test ok, check the filament circuit (R14701, U14752). Also check for correct screen voltage (190vdc - 420vdc)
End
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 4 of 4
THOMSON INC.